The players' first two moves initialize the center four
positions with one of 2 patterns:

o o o x
x x x o

A move consists of "outflanking" your opponent's
disc(s), then flipping the outflanked disc(s) to your colour.

To outflank means to place a disc on the board so that your
opponent's row (or rows) of disc(s) is bordered at each end by a disc of your colour. (A
"row" may be made up of one or more discs).

Here's one example: White disc A was already in place on
the board. The placement of white disc B outflanks the row of three black discs.

x o o o x

White flips the outflanked discs and now the row looks like
this:

x x x x x

Reversi Rules

Black always moves first.

If on your turn you cannot outflank and flip at least one
opposing disc, your turn is forfeited and your opponent moves again. However, if a move is
available to you, you may not forfeit your turn.

A disc may outflank any number of discs in one or more rows
in any number of directions at the same time - horizontally, vertically or diagonally. (A
row is defined as one or more discs in a continuous straight line ). See Figures 2 and 3.

All discs outflanked in any one move must be flipped, even
if it is to the player's advantage not to flip them at all.

A player who flips a disc which should not have been turned
may correct the mistake as long as the opponent has not made a subsequent move. If the
opponent has already moved, it is too late to change and the disc(s) remain as is.

Once a disc is placed on a square, it can never be moved to
another square later in the game.

If a player runs out of discs, but still has an opportunity
to outflank an opposing disc on his or her turn, the opponent must give the player a disc
to use. (This can happen as many times as the player needs and can use a disc).

When it is no longer possible for either player to move, the
game is over. Discs are counted and the player with the majority of his or her colour
discs on the board is the winner.

NOTE: It is possible for a game to end before all 64
squares are filled.